Conventionally, a plasma CVD (chemical vapor deposition) method is frequently used in semiconductor manufacturing facilities in order to form an insulating film on a substrate to be processed, such as a semiconductor wafer housed inside a reaction container. When using the plasma CVD method, a gas for forming the insulating film is introduced into the reaction container in which plasma has been generated by applying RF (radio-frequency) power between a susceptor for placing the substrate to be processed and a face plate constituting the reaction container, so that the insulating film is formed on a surface of the substrate. A plasma CVD device of this type is called a capacitively-coupled plasma CVD device, and is the most typical plasma CVD device. At this time, it is preferable that the insulating film be a compressive stress film having equal to or below 200 MPa, so as to suppress film detachment or an influence on element characteristics. An example of this technique is disclosed in the following Patent Document 1.
According to the following Patent Document 1, the plasma is generated with low RF power equal to or below 500 W, and the insulating film is formed at a film forming rate equal to or below 500 nm/min. The compressive stress of the insulating film thus formed is approximately 100 MPa. A protective film formed for the purpose of insulation between elements such as transistors or between interconnections, or of preventing entry of moisture or the like, is also required to have a stress equal to or below 200 MPa.